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Former shuttle astronaut and current ATK executive Charlie Precourt discussed the use of composite materials in a recent interview with SpaceFlight Insider. Photo Credit: NASA / ATK

Jason Rhian

December 7th, 2013

Charlie Precourt is very familiar with the solid rocket boosters (SRBs) produced by Utah-based ATK Aerospace Group. He should be, as he has relied on them to safely deliver him and the crews who rode with him to orbit four times.

ATK recently announced it had successfully completed filament winding on what is known as a pathfinder rocket booster case. The case is part of ATK’s efforts under NASA’s Research Announcement (NRA) Advanced Booster risk-reduction program and was constructed to validate the design of a full-scale version of the case.

During a recent interview with SpaceFlight Insider, Precourt detailed how ATK’s efforts will use cutting-edge technology, along with its extensive history with these legacy systems, to develop an advanced booster design that could be used on NASA’s new heavy-lift launch vehicle – the Space Launch System or SLS.

Precourt discussed what this recent accomplishment means in terms of NRA in general and SLS in particular.

SpaceFlight Insider: First off Charlie, thank you for taking the time out of your busy schedule to break down for our readers what completing the filament winding on the pathfinder version of the advanced booster means for NASA’s crewed deep space exploration efforts.

Precourt: “You’re welcome, this is an exciting time, and I hope I can convey some of what we have done to the folks who visit your website.”

Precourt: “Sure. NASA solicited, in the form of a research announcement, offerings that could reduce risk for future designs of an advanced booster that could be phased into the SLS program down the road as requirements dictate. We put together an offering geared principally toward simultaneously increasing performance while reducing cost. This was very challenging. Increasing performance is pretty intuitive – you want to reach deeper space destinations and also be able to launch larger payloads to support those exploration efforts.

“Regarding cost, there are challenges with both the expense of developing a new system as well as the cost to maintain and operate it. ATK’s offering focused on both of those aspects. How do we bring on great performance capabilities while decreasing cost for the life of the program? This is all part of the next step down the path of what we’ve been doing for some time – reducing cost from a manufacturing and reliability standpoint.”

Pathfinder is a scaled-down version of the type of segments which will be used on SLS. It’s purpose is to validate the design concept. Photo Credit: ATK

SpaceFlight Insider:Can you tell us a bit about the pathfinder advanced booster case? Why move away from steel boosters? What are the benefits of this new method?

Precourt: “We use both steel and fiber in our various solid rocket booster systems. The Trident D5 missile system for the U.S. Navy is composite and many of our commercial solid rocket motors are composite. We at ATK have a unique capability with composite materials. We build the entire, what I call the skeletal structure, of the Airbus A350. This is comprised of complex-shaped components that are produced through advanced automated processes. There are a number of advantages to using composites and our experience in using them led us to exploring them as an option for NASA.

“One benefit is the ability to form structures with a complex shape with the resulting product being better-tailored to the stresses the object would encounter. So instead of having components comprised solely of metal, which have stress locations that are corrected by strengthening joints and by beefing up the structure, we can have a single step in the manufacturing process that addresses the stresses the structure will encounter through tailoring the composite material. This is much more conducive to the unique manufacturing shapes and contours and so forth. From an engineering standpoint – that is a distinct advantage.

The NRA team poses in front of the freshly-completed Pathfinder booster segment. Photo Credit: ATK

“There is also a weight advantage in certain applications where the material can be lighter than in a corresponding metal structure. That’s less of an issue for a first-stage booster because you aren’t carrying the weight to orbit; you are only carrying it through the first stage. Nonetheless, weight is always a consideration for aerospace components – it is crucial to keep weight down as much as possible.

“When you want higher performance, you have to be able to manage higher stresses, and composite materials can be designed, shaped and tailored to handle higher loads in the performance of the booster. There’s a flexibility there that should be considered in a future design. I do expect both steel and composite systems will continue to be used in all kinds of different applications in our industry for some time to come.”

SpaceFlight Insider:What are the possible drawbacks to a booster case that is produced in this manner?

Precourt: “We’ve been using them for so long on other systems, we feel like we have a very strong grasp of how to manage drawbacks. Taking lessons we’ve learned along the way, we’ve integrated elements that compensate for them into the design. Fundamentally, even in the event of designing a new steel case, it really comes down to validating a design and then testing.

“When you have a design, you put together a thickness profile and you need to test and validate that it is going to have the resulting expected performance and no surprises from a load or structures standpoint. It’s a different engineering problem to solve because composite materials fracture differently than metals do.”

The first unmanned test flight of NASA’s Space Launch System is currently scheduled to take place in 2017. Image Credit: NASA

SpaceFlight Insider:When and in what manner will the pathfinder booster be used? Why is it important?

Precourt: “Pathfinder is meant to get you as far along in development of a total system as you can, in as cost-effective a manner as possible. Pathfinder is not full-scale and it does not comprise everything. It is intended to allow us discover how these technologies interact early enough to see where we might need to take the next steps in the application for the final design we might use.”

SpaceFlight Insider:So now that you’ve demonstrated how these technologies behave on a smaller scale, will you be moving on to a larger version?

Precourt: “The rationale behind a NASA Research Announcement and Advanced Booster Risk Reduction Program – is to reduce risk with focused efforts on potential new technologies, to see where their application limitations might cause a problem on a full-scale program later. The full-scale application is keenly in mind.”

While superficially the boosters being developed by ATK for SLS might resemble those used during the space shuttle program – they are different in many ways from their legacy counterparts. Photo Credit: James N. Brown

SpaceFlight Insider:ATK has released estimates that this new method reduces the amount of time that is required to produce boosters by some 46 percent – how much of a cost savings per booster does this create?

Precourt: “When the shuttle program ended, we were presented with an opportunity to improve on a really great system and to make it even better. In determining how we could improve from a cost standpoint, what we did was assess the value stream. An industry’s value stream is where its product is manufactured all the way—in our case, through to flight. Every step along the way there is value added to the product by the next step in the process. So we took that process apart and looked at what we were doing that maybe wasn’t necessary anymore or where we could use new manufacturing technologies. We dissected the processes and looked at ways where we could modernize them. It was a much larger, incremental step in improvements than we were ever able to insert during the shuttle program, due to the operational nature of the program at the time. We called this effort Value Steam Mapping.

“The 46 percent number becomes meaningful because it demonstrates the significance of these improvements and the fact that you can get three-and-a-half million pounds of thrust, from a booster that is highly-reliable at a lower cost. That is what we have been focused on in order to enable NASA’s mission of deep space exploration, within the confined budget. We want more performance for less money, and that’s been our focus.”

Precourt rode fire into the black four times. Some of his orbital missions were to the pre-cursor mission to the International Space Station – the Shuttle-Mir program. Photo Credit: NASA

SpaceFlight Insider:Without a doubt, one of the most intriguing aspects of ATK’s efforts has been the Value Stream Mapping (VSM) process – how great a role in producing the pathfinder booster?

Precourt: “It was completely integrated into the process. The idea behind it was to create more performance for less cost. So, it really was a key element of that whole offering.”

SpaceFlight Insider:Are there other ways that ATK is contributing to NASA’s NRA program and if so – in what way?

Precourt: “There has been a lot of discussion about the cost associated with the management model of a program, and when I say management model, I’m talking about the work distribution between the agency and the project teams on the agency side and on the contractor’s side. We call that insight and oversight.

“The NRA offers a unique place to test models of management of the system such that the amount of effort to do certain aspects of the program management could be streamlined and the workforce could be redistributed to do other things. Essentially, we asked ourselves: ‘Could we build a rocket with fewer people?’

“That’s a real delicate thing to do and a very challenging thing to manage. However, on the NRA we were able to explore that. I think you’ll hear praise from NASA for the team that is developing this as it is extremely streamlined and viewed as agile and successful in its management decisions.”

SLS has been touted as the heavy-lift booster which will send crews to destinations beyond the orbit of Earth for the first time in more than four decades. Image Credit: NASA

SpaceFlight Insider:SLS is slated to conduct its first flight in 2017 with flights taking place every four years or so. Is it possible that this new method of producing boosters could help to accelerate this?

Precourt: We are looking at safe ways to reduce both the cost as well as the time it takes to produce these components. I would be the first to cheer for more flights sooner, and I think that we are being smart about focusing on affordability and that our efforts will lead us to that capability. It won’t just be the booster either, it will be the engines, the tanks, the core structure, the ground infrastructure – all of that has to come together to enable the acceleration of schedules.

“Short answer to your question – the affordability part of the equation is extremely important to making flight rates viable.”

SpaceFlight Insider:If you had the opportunity to tell the public the most important thing about this recent milestone completion – what would it be?

Precourt: “I would say that while it might seem counterintuitive that we can increase performance while producing something that costs less, we actually are going to be able to achieve that. We are transitioning to a new program with a new design. I have very high confidence that we can get a far more efficient cost profile to NASA. Thanks to the technology evolution and capabilities evolution, it is an achievable task, and we’ve shown through this recent milestone that we are on our way to enable that.”

Image Credit: ATK

SpaceFlight Insider:Semi off-topic question, you’ve rode fire to orbit four times on boosters of a somewhat similar design. How do you think a ride using boosters produced in this manner would compare to a ride on a traditionally-produced booster?

Precourt: “I think the most notable thing about the ride is the sudden force in the back at liftoff. Then you would feel a gentle rumbling from the thrust from the system as you ride through first stage. During the first stage, you are still in the atmosphere. In the case of the shuttle, the boosters are producing 3 million pounds of thrust each. In SLS we estimate there will be three-and-half or more each. I think the impression the crews will get is that the ride is even more powerful than shuttle. When I think of ‘the ride’ I think of the push in the back and the scale of the acceleration that continues for eight-and-a-half minutes. I think it will be very similar to shuttle. However, the amount of power that will be delivered? It’s going to be dramatically higher.”

SpaceFlight Insider:Charlie, we know that you have a great many things on your schedule and we want to thank you for spending time chatting with us today.

Precourt: “Thank you. I really feel it’s important to share with the public what we are doing to open the door to human deep space exploration missions.”

As mentioned, Precourt is an experienced former NASA astronaut. He became an astronaut in 1991. His first space shuttle mission was two years later during 1993’s STS-55 (which used space shuttle Columbia). Two years after that, in 1995, he was the pilot of space shuttle Atlantis during STS-71. This was the first mission to the Russian space station Mir; it would serve him well for his next assignment.

Charlie Precourt. Photo Credit: ATK

After STS-71 mission he was stationed at the Yuri Gagarin Cosmonaut Training Center, located in Star City, Russia. He would serve there for one year, leaving in 1996. While in Russia he served as the Director of Operations.

Upon his return to the U.S., he was assigned to STS-84. This mission was his first mission where he served as commander. Precourt led fellow crew members riding in Atlantis to Mir. Precourt’s final trip into the black was on space shuttle Discovery during STS-91. Like Precourt’s two prior flights – this was a trip to Mir. It was the last shuttle mission to the Russian space station. With the conclusion of STS-91 Precourt had logged 932 hours in space.

Precourt left the astronaut program in 2002 to join the International Space Station Program as the deputy program manager. In 2005 he left NASA to join ATK. He serves as the company’s vice president and general manager of ATK Aerospace Group’s Space Launch Division where one of his focuses is on the next-generation human-rated launch system that is the SLS.

The next step in the program is a test flight of Orion less than a year away and the first test flight of the entire system, SLS and Orion, currently scheduled for 2017. The first crewed flight is slated to take place four years later in 2021. Both NASA and ATK hope that by using cutting-edge technologies, costs will be decreased and the overall program will become more streamlined.

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Jason Rhian

Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.